The inquiry surrounds child trafficking from Romania and the welfare of the children involved.

Police suspect poor families in eastern Europe may be forced into allowing gangs to take their children into the UK to carry out offences such as pickpocketing and thefts near cash machines.

The gangs are believed to have taken the children into west London to commit the crimes.

The youngsters, who ranged from as young as the baby to 17 years old, are being cared for by Slough Borough Council.

Detectives will investigate whether any of them were involved in suspected offences and whether they were taken from their families and illegally trafficked into the UK.

A Metropolitan Police spokesman said many of the raided properties, in the Chalvey area of the town, were "high occupancy" with large numbers of people inside.

Commander Steve Allen, of the Met Police, said the operation was about "targeting those behind organised crime networks on the streets of London and the criminal exploitation of children".

He added: "With promises of a financial return, some poor families surrender their children who are subsequently forced to commit crime.

"We continue to work closely with, and share intelligence with, the Romanian authorities."

'Reunite families'

Supt Pete Davies, of Thames Valley Police, said: "I appreciate many residents would have woken up to a rather large police presence in Chalvey this morning, however it is our intention to ensure that any disruption is kept to a minimum.

"Members of the neighbourhood policing team are on duty and will be able to address local concerns."

Officials from Slough Borough Council accompanied police on the planned intelligence-led raids.

Ruth Bagley, chief executive of the council, said: "Our main focus in this operation is on the welfare of the children who are potentially being exploited.

"We will ensure that any children who are presented to the council, receive the appropriate level of care, and efforts will be made to reunite them with their families."